Automatic loin-pulling apparatuses have been developed over the years for removing excess fat and also the belly loin area of an animal carcass, i.e., as a step towards final cutting and packaging of the loin, belly, and fatback. Such automated loin pulling apparatuses include the devices disclosed in U.S. Pat. Nos. 6,089,968 and 6,547,658, for example, which disclose loin knife mechanisms for use with associated meat carcass processing machines. Some such knife apparatuses utilize bent knife blades, including dual blade assemblies.
There is an ongoing high volume of meat carcasses, e.g., pork carcasses, being processed every work day. Thus, an improper knife blade placement measuring only 0.1 inch, for example, can cause drastic loss in yields and price reductions in the belly, loin, and fatback portions, or increase further hand-trimming operations downstream. Thus, the individual loin knives must be carefully shaped, and also able to cleanly cut in a smooth fashion. Further, such blade assemblies must be formed so as to withstand hundreds of thousands of cuttings, e.g., 10,000 cuttings per day or more for multiple months, before needing replacement, so as to prevent costly downtime due to knife blade maintenance and/or change-out.
In the known dual blade loin knife assemblies of the prior art, see for example U.S. Pat. No. 6,547,658, there are two kinds of blades. First, there are so-called “Z-blades”, operable to separate the loin portion from the belly portion of a hog carcass, as well as leave a so-called “belly shelf’ and fingers of lean meat on the belly of a hog, for appearance and for superior bacon yields. Further, there are the so-called “J-blades,” which work from the chine or backbone side of the carcass, used to separate the fatback portion from the loin portion.
However, due to the method of manufacturing such prior art blades, problems exist in the available normal cycles of usage of such blades, requiring relatively frequent machine downtime for blade replacement. Further, some meat processing machines necessitate that the J-blades have a so-called outwardly-extending “tab” portion, wherein an elongated diverter bar member is held by the tab member, as used to direct and position the trailing slab of fatback as it is cut from the pork carcass. As to such prior art “tabbed” style J-blades, it has been found that those tab portions often break prematurely next to their welds, i.e. before the normal life of the tabbed J-blade has been used up.
Further, the shapes used for the so-called “belly shelf” cutting portions of the prior art Z-blades (as used for cutting a shelf through the longitudinal middle of the finger lean meat of the carcass) did not permit the resultant cut belly shelf to reach the customers' maximum permitted dimensional specification. Thus, unnecessarily large amounts of belly yield had to thereafter be removed off the loin portion, and they became less-desirable trimmings (which are then worth substantially less). Further yet, the prior art style of “J-blades” have, due to their specific shapes, left unusually large portions of excess fatback on the pulled loin portion of the loin middle, and hence also provided poor fatback yields. That, in turn, necessitates extra effort down-the-line in hand trimming operations, resulting in both extra labor costs, as well as a reduced amount of “good” (i.e. connected) fatback, i.e. which is desirable due to the higher price received for sales of the trimmed fatback portion of the carcass when sold as one piece.
More specifically, meat processors using such dual blade loin knife-type machines require that a satisfactorily “belly shelf’ cut be made by the Z-blade, i.e. one that both falls within their dimensional specifications (typically some 2.5 inches±0.2 inches in length) and which also gets sufficient “fingers of lean” meat (found on the back side of the bacon, for good bacon yield), yet which blades also do not cut into or otherwise expose the loin eye meat (which would reduce the value of that select cut of meat). Further, most customers of the cut and pulled pork loins have a specification for their processors that permit no more than one-quarter inch of fat cover on the loin meat. Thus, there is a need to be able to trim the fatback over the loin as close as possible to the loin eye meat, yet again without cutting into and exposing the same.
Further, there has been an inability with the prior art types of J-blades to be adjusted sufficiently vertically, i.e. to be moved substantially down close to the split conveyor belt bed relative to the meat carcass, due to their specific blade configuration. This inability to closely adjust to the bed profile created substantial yield loss for such prior J-blades. This was especially the case when such prior J-blades where used in a meat processing plant which was running so-called “European White” hogs, as those type of pork carcasses have very little fat, and the red meat portions are located substantially close to the skin. Thus, the prior J-blades were not of a shape that could be adjusted effectively relative to the conveyor belts, and thus, they could not run at desirable high yield rates, for processing such “European White” hogs.
Further yet, some processing customers require at the so-called “shoulder end” of the loin portion of the carcass, where some amount of so-called “false lean” meat is present, that the majority of such false lean stay on the loin, yet they also want a small portion of such false lean to stay on the belly, so as to have sufficient meat in the remaining bacon portion.
Additional problems with the known prior art dual blades include that they are formed with relatively rough surfaces that create a substantial amount of cutting drag through the carcass. This in turn places substantial side loads on the loin puller machine's blade-related components, such as the bushings, linkage parts, blade-holding components, and bearings. Thus, such blade-related components often require early replacement, necessitating machine downtime. Also, if such worn components are not properly replaced, then due to the end-play that they create, there are yet additional yield losses, broken carcass bones, and improper meat cutting, resulting then in yet additional lost revenue.
Thus, there has been a need for improved “Z-blades” and “J-blades” for use in meat production operations, especially for use in pulling loins in pork carcass processing plants.